Unitary cylinder with piston retaining means

ABSTRACT

A piston and cylinder assembly wherein the cylinder includes a closed end portion at one end and a piston-receiving bore at the other end. The cylinder includes a radially extending fluid inlet port communicating with the interior of the cylinder. A piston is receivable through the bore and includes an opening extending transversely therethrough which is adapted to be aligned with the inlet port. A pin is adapted to be inserted through the port into the opening in the piston and serves to limit the movement of the piston outwardly from within the cylinder to retain the piston within the cylinder during normal reciprocating movement thereof.

United States Patent Roland 1 Dec. 10, 1974 1 1 UNI'IARY CYLINDER WITH PISTON 2,987,046 6/1961 Atherton 92/128 RETAINING MEANS 2,997,026 8/1961 'Zimmerer .1 92/128 3,065,734 11/1962 Molzahn 92/128 Inventor: Murray C Roland, Fruitland, 3.191506 6/1965 Ledeen 92/162 Ontario, Canada [73] Assignee: International Harvester Company,

Chicago, Primary ExaminerManuel A. Antonakas [22] Filed: Mar. 4, 1970 Assistant Examiner-R. H. Lazarus [21] pp No: 19,143 Attorney, Agent, or Firm-Neal C. Johnson; Floyd 8.

Harman Related US. Application Data [60] Division of Ser. Nov 796,289, Jan. 21, 1969I Pat. No.

3,538,575, which is a continuation of Ser. No, ABSTRACT 644263 June 1967 abandoned A piston and cylinder assembly wherein the cylinder includes a closed end portion at one end and a piston- [52] US. Cl. 92/128, 92/162 receiving bore at the other The cylinder includes [51] 1].. C1 F16] a radially extending fluid inlet p communicating [58] held of Search 92/165 with the interior of the cylinder. A piston is receivable 92/162 through the bore and includes an opening extending transversely therethrough which is adapted to be [56] References cued aligned with the inlet port. A pin is adapted to be in- UNITED STATES PATENTS serted through the port into the opening in the piston 1,739,644 12 1920 Lug]; 92 128 and serves to limit the movement of the piston outl.928,533 9/1933 92/53 wardly from within the cylinder to retain the piston 2,372,694 4/1945 29/1564 X within the cylinder during normal reciprocating move 2,380,607 Nystrom X ment thereoi 2,724,368 11/1955 Miller 92/128 2.915.046 12/1959 Larsen 92/169 6 Claims, 3 Drawing Figures UNITARY CYLINDER WITH PISTON RETAINING MEANS This application is a division of applicant's copending application Ser. No. 796,289 filed Jan. 2], 1969, now US. Pat. No. 3,538,575, which is a continuation of applicants application Ser. No. 644,263 filed June 7, 1967, now abandoned.

BACKGROUND OF THE INVENTION The increasing use of unitary or integrally formed bydraulic cylinders has presented a problem relating to the means by which the piston is mounted in the cylinder and retained therein throughout normal operation. More specifically such cylinders are frequently cast in one piece or formed of welded construction such that the piston must be inserted into the completed cylinder through the bore which slidably and sealingly engages the piston in normal use. The specific problem in units of the above type relates to providing satisfactory means for retaining the piston in the cylinder by also permitting removal of the piston when desired.

Various methods have been proposed including the use of snap rings, threaded extensions and the like which must be introduced into the cylinder and coupled to the piston. In many of these systems the cylinder must be machined or cast into a particular configuration to accommodate the ingress and internal positioning of the retaining member for subsequent coupling to the piston within the cylinder. A specific example of a prior system involves drilling and threading an access opening into the cylinder for receiving the retaining members and also providing a threaded plug to close the opening after the piston is operatively installed. The cost of machining and fabricating the unit is accordingly increased. Other prior art arrangements require the introduction of a tool into a special toolacess opening in the cylinder to remove the retaining members from the piston to permit its withdrawal from the cylinder.

SUMMARY With the foregoing in mind it is accordingly a primary object of the invention to provide a piston and cylinder assembly utilizing a unitary or integrally formed type of cylinder while providing a greatly simplified and effective means for retaining the piston within the cylinder for normal operation.

Another object is to provide a piston-cylinder assembly which permits the cylinder to be constructed without any special or extra features being required for accommodating the means for coupling and retaining the piston in the cylinder, to the end that the cost of design and manufacturing are reduced to a minimum heretofore unattainable.

Another object is to provide an assembly of the above type which enables the piston to be removed quickly and easily without requiring tools and special tool-access openings in the cylinder.

Briefly these and many other objects and advantages of the invention are attained by providing a piston and cylinder assembly including a unitary cylinder defining a cylindrical working chamber into which an axial bore communicates for slidably supporting a piston receivable in the chamber. The cylinder also includes a fluid inlet port communicating radially into the chamber.

The piston of the assembly includes a transverse opening defined therethrough in a portion thereof received and reciprocable within the chamber during operation. The piston is movable with respect to the cylinder enabling the opening to be axially aligned with the fluid inlet port.

The assembly includes means insertable through the fluid inlet port into the opening in the piston for limiting movement of the piston outwardly from the chamber during operation of the assembly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a sectional view of;the cylinder and piston assembly of the invention illustrating the orientation of the piston with respect to the fluid inlet port of the cylinder enabling a retainer pin to be installed in the assembly;

FIG. 2 is a sectional view similar to FIG. I illustrating the pin received in the assembly; and

FIG. 3 is a sectional view illustrating the invention in assembled relation.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1 there is shown a cylinder indicated generally at 10 which includes a tubular portion 11 joined as by welding to an end closure member 12 having a coupling-receiving opening 13 defined transversely therethrough. An end portion 14 is joined as by welding to the opposite end of the tubular portion 11 such that the members II, 12 and 14 provide a unitary cylinder defining a longitudinally cylindrical working chamber 15 therein.

The end portion 14 includes a central axially extending bore 16 communicating with the working chamber 15. The bore 16 is of a diameter less than the internal diameter of the working chamber 15 and is adapted to slidably and sealingly support a cylindrical piston 17 therein as shown. Appropriate sealing means such as an The cylinder 10 includes a fluid inlet port 21 communicating radially into the working chamber 15 for threadedly receiving a suitable fluid line (not shown) of a pressure system.

In accordance with a feature of the invention the portion of the piston 17 operatively disposed within the chamber 15 includes a longitudinally cylindrical opening 22 defined transversely and diametrically therethrough as shown. The piston 17 is movable with respect to the cylinder 10 such that the opening 22 may be axially aligned with the fluid inlet port 21. A longitudinally cylindrical pin 23 is provided for insertion through a port 21 into the opening 22 as shown in FIG. 2. The pin 23 has a diameter slightly less than the diameter of the opening 22 so as to be freely slidable transversely of the piston within limits defined by the engagement of the pin 23 with the walls of the tubular portion 11. It has been found in practice that the frictional engagement of the pin 23 against the walls of the tubular portion 11 is negligible during reciprocation of the piston.

The pin 23 has a length less than the diameter of the chamber but preferably greater than the total of the diameter of the piston and the radial distance from the piston to the chamber wall. Accordingly the ends of the pin 23 will protrude radially from the piston 17 at the opposite ends of the opening 22 regardless of the relative diameters of the piston and the working chamber. By this arrangement both ends of the pin are positioned to contact the end portion 14 to limit the outward stroke of the piston, without creating bending forces on the piston.

The opening 22 is preferably drilled through the piston 17 parallel to the aperture for purposes to be described.

In the assembly of the cylinder-piston unit of the invention, the piston 17 is inserted through the bore 16 to extend into the working chamber 15 of the cylinder 10. Since the opening 22 and aperture 20 are parallel, the piston may be quickly and easily positioned to align the opening 22 with the inlet port 21 by visual reference to the alignment or position of the aperture 20 with respect to the inlet port 21. When the opening 22 is aligned with the port 21' the pin 23 is simply dropped into the port 21 in the direction of arrow A and assumes the position shown in FIG. 2. The piston 17 is then rotated about its longitudinal axis to position the pin 23 out of alignment with the port 21 as shown in FIG. 3. Visual reference to the position or orientation of the aperture 20 with respect to the inlet port 21 provides an external indication of the position or orientation of the pin 23 within the cylinder 10.

it will be apparent that the pin 23 may be quickly and easily withdrawn from the piston and cylinder assembly, permitting the piston to be withdrawn from the bore 16, by again aligning the opening 22 with the port 21. The entire assembly may then be disposed to permit the pin 23 to fall out by gravity, or a magnet may be inserted into the port 21 for removing the pin.

The above described invention results in a simple, effective, and low cost assembly eliminating many features previously thought to be necessary to obtain the stated objectives.

The avarious changes falling within the scope and spirit of the invention will occur to those skilled in the art. The piston and cylinder assembly is therefore not to be thought of as limited to the specific embodiment set forth.

What is claimed is:

l. A piston and cylinder assembly, comprising in combination:

a unitary cylinder defining a cylindrical working chamber of a given diameter and having an axial bore of a diameter less than said given diameter communicating with said chamber, said cylinder including a fluid inlet-outlet port communicating radially into said chamber;

a piston slidably received in said bore and adapted to reciprocate in said chamber, said piston having a transverse opening defined therethrough in a portion thereof received in said chamber; and

means retained in said opening completely within said chamber for limiting the movement of said piston outwardly from said chamber through said bore, said port and said opening being in alignment to permit said means to be inserted into and removed from said opening through said port, said piston including a transverse aperture defined therein in a portion thereof outwardly of said chamber and extending parallel to said transverse opening, whereby said piston may be positioned to align said opening with said port by visual refer ence to the alignment of said aperture with respect to said port enabling insertion and withdrawal of said means with respect to said cylinder and piston.

2. The subject matter of claim 1, in which said means comprises a pin having a length less than said given diameter but sufficient to protrude radially from said opening in said piston.

3. The subject matter of claim 2, in which said pin is longitudinally cylindrical in configuration, and in which said transverse opening is longitudinally cylindrical and ofa diameter slightly greater than said pin enabling said pin to be freely slidable in said opening.

4. The subject matter of claim 1, in which said means comprises a pin having a length in excess of the total of the diameter of said piston and the radial distance from said piston to thewall of said chamber, but less than said given diameter, whereby said pin protrudes from opposite ends of said opening.

5. A piston and cylinder assembly, comprising in combination:

a unitary cylinder defining a longitudinally cylindrical working chamber of a given diameter, said cylinder including an end portion having an axial bore defined centrally therethrough in communication with said chamber, said bore having a diameter less than said given diameter, said cylinder including a fluid inlet-outlet port communicating radially into said chamber;

a piston slidably received in said bore and adapted to reciprocate in said chamber, said piston having a transverse opening defined therethrough in a portion thereof received in said chamber, a pin retained in said opening completely within said chamber, said port and said opening being aligned to permit said pin to be inserted into and removed from said opening through said port, said pin having a thickness less than the cross sectional dimension of said opening enabling said pin to be freely slidable transversely of said piston within limits defined by the engagement of said pin with the walls of said chamber, whereby said pin will engage said end portion of said cylinder for limiting movement of said piston outwardly from said chamber through said bore, said piston including a transverse aperture defined therethrough in a portion thereof outwardly of said chamber and extending parallel to said transverse opening, whereby said piston may be positioned to align said opening with said port by visual reference to the alignment of said aperture with respect to said port enabling insertion and withdrawal of said pin with respect to said cylinder and piston.

6. The subject matter of claim 5, in which said pin has a length in excess of the total of the diameter of said piston and the radial distance from said piston to the wall of said chamber, but less than said given diameter, whereby said pin protrudes from opposite ends of said opening. 

1. A piston and cylinder assembly, comprising in combination: a unitary cylinder defining a cylindrical working chamber of a given diameter and having an axial bore of a diameter less than said given diameter communicating with said chamber, said cylinder including a fluid inlet-outlet port communicating radially into said chamber; a piston slidably received in said bore and adapted to reciprocate in said chamber, said piston having a transverse opening defined therethrough in a portion thereof received in said chamber; and means retained in said opening completely within said chamber for limiting the movement of said piston outwardly from said chamber through said bore, said port and said opening being in alignment to permit said means to be inserted into and removed from said opening through said port, said piston including a transverse aperture defined therein in a portion thereof outwardly of said chamber and extending parallel to said transverse opening, whereby said piston may be positioned to align said opening with said port by visual reference to the alignment of said aperture with respect to said port enabling insertion and withdrawal of said means with respect to said cylinder and piston.
 2. The subject matter of claim 1, in which said means comprises a pin having a length less than said given diameter but sufficient to protrude radially from said opening in said piston.
 3. The subject matter of claim 2, in which said pin is longitudinally cylindrical in configuration, and in which said transverse opening is longitudinally cylindrical and of a diameter slightly greater than said pin enabling said pin to be freely slidable in said opening.
 4. The subject matter of claim 1, in which said means comprises a pin having a length In excess of the total of the diameter of said piston and the radial distance from said piston to the wall of said chamber, but less than said given diameter, whereby said pin protrudes from opposite ends of said opening.
 5. A piston and cylinder assembly, comprising in combination: a unitary cylinder defining a longitudinally cylindrical working chamber of a given diameter, said cylinder including an end portion having an axial bore defined centrally therethrough in communication with said chamber, said bore having a diameter less than said given diameter, said cylinder including a fluid inlet-outlet port communicating radially into said chamber; a piston slidably received in said bore and adapted to reciprocate in said chamber, said piston having a transverse opening defined therethrough in a portion thereof received in said chamber, a pin retained in said opening completely within said chamber, said port and said opening being aligned to permit said pin to be inserted into and removed from said opening through said port, said pin having a thickness less than the cross sectional dimension of said opening enabling said pin to be freely slidable transversely of said piston within limits defined by the engagement of said pin with the walls of said chamber, whereby said pin will engage said end portion of said cylinder for limiting movement of said piston outwardly from said chamber through said bore, said piston including a transverse aperture defined therethrough in a portion thereof outwardly of said chamber and extending parallel to said transverse opening, whereby said piston may be positioned to align said opening with said port by visual reference to the alignment of said aperture with respect to said port enabling insertion and withdrawal of said pin with respect to said cylinder and piston.
 6. The subject matter of claim 5, in which said pin has a length in excess of the total of the diameter of said piston and the radial distance from said piston to the wall of said chamber, but less than said given diameter, whereby said pin protrudes from opposite ends of said opening. 